Method for producing a catalyst for homo-or co-polymerization of ethylene

ABSTRACT

The present invention provides a method for producing a new catalyst of high polymerization activity for homo- or co-polymerization of ethylene, or more particularly a method for producing a titanium solid complex catalyst supported on a carrier containing magnesium, wherein said catalyst is capable of producing polymers of high bulk density and narrow particle size distribution with few fine particles.

TECHNICAL FIELD

[0001] The present invention provides a method for producing a catalystfor homo-polymerization or co-polymerization of ethylene, or moreparicularly a method for producing a high-activity titanium solidcomplex catalyst supported on a carrer containing magnesium, whereinsaid catalyst is capable of producing polymers of high bulk density andnarrow particle size distribution with low content of fine particles.

BACKGMUND OF THE INVENTION

[0002] Catalysts containing magnesium for polymerization orco-polymerization of ethylene are known to have very high catalyticactivities and to accord polymers of high bulk density, which aresuitable for liquid phase or gas phase polymerization. By liquid phasepolymerztion of ethylene, it denotes a polymerization process performedin a medium such as bulk ethylene, isopentane, or hexane, and as for theimportant characteristics of catalysts used in this process, there areas follows: high catalytic activity, bulk density of the resultantpolymers, the content of low molecular weight molecules of the resultantpolymers dissolved in a medium, the particle distribution of theresultant polymers, and the existence of fine particles within theresultant polymers.

[0003] Many of the titanium-based catalysts containing magnesium forolefin polymerization, and the manufacturing methods thereof have beenreported. Especially, many processes making use of magnesium solutionsto obtain catalysts which can generate olefin polymers of high bulkdensity have been known. There is a means of obtaining a magnesiumsolution by reacting magnesium compounds with such electron donors asalcohol, amine, cyclic ether, or organic carboxylic acid in the presenceof a hydrocarbon solvent. As for the cases of use of alcohol, they aredisclosed in U.S. Pat. Nos. 3,642,746, 4,336,360, 4,330,649, and5,106,807. Further, the methods for the production of catalystscontaining magnesium by reacting the said liquid-phase magnesiumsolution with a halogenated compound such as titanium tetrachloride arewell known. Such catalysts provide high bulk density to the resultantpolymers, but there is much yet to be improved with respect to theircatalytic activities or hydrogen reactivities. Moreover,tetrahydrofuran, a cyclic ester, has been used as a solvent for amagnesium compound in U.S. Pat. Nos. 4,477,639 and 4,518,706.

[0004] Meanwhile, U.S. Pat. Nos. 4,847,227, 4,816,433, 4,829,037,4,970,186, and 5,130,284 have reported the use of such electron donorsas dialkylphthalate, phthaloyl chloride, etc. in reaction with thetitanium chloride compound for the production of olefin polymerizationcatalysts of superior polymerization activity, which are capable ofenhancing the bulk density of resultant polymers.

[0005] U.S. Pat. No. 5,459,116 has reported a method of production of atitanium solid catalyst by contact-reacting a magnesium solutioncontaining an ester having at least one hydroxyl group as an electrondonor with a titanium compound. By this method, it is possible to obtaina catalyst of high polymerization activity, which accords high bulkdensity to resultant polymers, but there is room for yet moreimprovements.

[0006] As shown above, there is a need for the development of newcatalysts for homo-polymerization or co-polymerization of ethylene forproducing polymers with the following characteristics: a simplemanufacturing process, high polymerization activity, high bulk densityfor polymers by means of controlling the catalyst particles, and inparticular, a narow particle size distribution with few fine particles.In the present invention, therefore, it is intended to provide a methodof producing, from low-cost compounds via a simple process, a catalysthaving excellent catalytic activity, capable of producing polymers ofhigh bulk density and nariow particle size distribution with few fineparticles. Further, the specific production process of catalysts and thesteps thereof as disclosed in the present invention have never beenreported in the prior art.

SUMMARY OF THE INVENTION

[0007] Consequently, the objective of the present invention is toprovide a new method for producing a catalyst for homo-polymerization orco-polymerization of ethylene, wherein said catalyst has high catalyticactivity, which is capable of producing polymers of high bulk densityand narrow particle size distribution with few fine particles.

[0008] Another objective of the present invention is to provide a simpleprocess for producing a catalyst for homo-polymerization orcopolymerization of ethylene.

[0009] Still other objectives and the utility of the present inventionwill become apparent as references are made with respect to thefollowing descriptions and the claims thereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The catalyst for homo-polymerization or co-polymerization ofethylene according to the present invention is produced by a simple yetefficient manufacturing process, which compass (i) preparing a magnesiumsolution by contact-reacting a halogenated magnesium compound withalcohol, and adding mineral oil to adjust the viscosity of saidmagnesium solution; (ii) reacting said solution with an ester compoundhaving at least one hydroxyl group and a silicon compound having atleast one alkoxy group; and (iii) producing a solid titanium catalyst byadding a mixture of a titanium compound and a silicon compound.

[0011] Types of halogenated magnesium compounds used in the presentinvention are as follows: di-halogenated magnesiums such as magnesiumchloride, magnesium iodide, magnesium fluoride, and magnesium bromide;alkymagnesium halides such as methylmagnesium halide, ethylmagnesiumhalide, propylmagnesium halide, butylmagnesium halide, isobutylmagnesiumhalide, hexylmagnesium halide, and amylmagnesium halide; alkoxymagnesiumhalides such as methoxymagnesium halide, ethoxymagensium halide,isopropoxymagnesium halide, butoxymagnesium halide, octoxymagnesiumhalide; and aryloxymagnesium halides such as phenoxymagnesium halide andmethyl-phenoxymagnesium halide. Of the above magnesium compounds, two ormore compounds can be used in a mixture. Further, the above magnesiumcompounds can be effectively used in the form of a complex compound withother metals.

[0012] Of the compounds listed above, some can be represented by asimple formula, but the others cannot be so resented depending on theproduction methods of magnesium compounds. In the latter cases, it canbe generally regarded as a mixture of some of the listed compounds. Forexample, the following compounds can be used in the present invention:such compounds obtained by reacting magnesium compounds withpolysilolxane compounds, silane compounds containing halogen, ester, oralcohol; and such compounds obtained by reacting magnesium metals withalcohol, phenol, or ether in the presence of halosilane, phosphoruspentachloride, or thionyl chloride. However, the preferable magnesiumcompounds are magnesium halides, especially magnesium chloride oralkylmagnesium chloride, preferably those having respectively an alkylgroup of 1˜10 carbons; alkoxymagnesium chlorides, preferably thosehaving respectively 1˜10 carbons; and aryloxymagnesium chlorides,preferably those having respectively 6˜20 carbons. The magnesiumsolution used in the present invention can be produced as solution byusing the aforementioned magnesium compounds in the presence ahydrocarbon solvent or in the absence thereof, in an alcohol solvent.

[0013] As to the types of hydrocarbon solvents used in the presentinvention, they include aliphatic hydrocarbons such as pentane, hexane,heptane, octane, decane, and kerosene; alicyclic hydrocarbons such ascyclobenzene, methylcyclobenzene, cyclohexane, and methylcyclohexane;aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene,cumene, and cymene; and halogenated hydrocarbons such asdichloropropane, dichloroethylene, trichloroethylene, carbontetrachloride, and chlorobenzene.

[0014] When a magnesium compound is converted into a magnesium solution,alcohol is used in the presence of the aforementioned hydrocarbons or inthe absence thereof. The types of alcohol include those containing 1˜20carbon atoms, such as methanol, ethanol, propanol, butanol, pentanol,hexanol, octanol, decanol, dodecanol, octadecyl alcohol benzyl alcohol,phenylethyl alcohol, isopropyl benzyl alcohol, and cumyl-alcohol,although alcohol containing 1˜12 carbon atoms is preferable. The averagesize of a target catalyst and its particle distribution can varyaccording to the types of alcohol, the total contents, the types ofmagnesium compounds, and the ratio of magnesium to alcohol, etc.Nevertheless, the total amount of alcohol required to obtain themagnesium solution is at least 0.5 mol per each mole of magnesiumcompounds, preferably about 1.0˜20 mol, or more preferably about 2.0˜10mol.

[0015] During the production of magnesium solution, the reaction of amagnesium compound with alcohol is preferably carried out in thepresence of a hydrocarbon medium. The reaction temperature, whilevariable depending on the types and the amount of alcohol, is at leastabout −25° C., preferably −10˜200° C., or more preferably about 0˜150°C. It is preferable to carry out the reaction for about 15 minutes ˜5hours, preferably for about 30 minutes ˜84 hours.

[0016] In order to adjust the viscosity of the magnesium solutionproduced according to the present invention, mineral oil is used Byadjusting the viscosity of the magnesium solution, shapes, particle sizeand distribution of catalysts can be more easily controlled.Accordingly, it was discovered that by using said catalyst the bulkdensity and the particle distribution of the resultant polymers could beimproved.

[0017] As for the types of mineral oil, white oil, parafinic hydrocarbonoil (e.g., Nujol), or silicone oil can be used. The viscosity of mineraloil used in the present invention is 5-85 centistoke at 40° C., orpreferably 60-75 centistoke.

[0018] Of the electron donors used in the present invention, the estercompounds respectively having at least one hydroxyl group includeunsaturated aliphatic acid esters respectively having at least onehydroxyl group, such as 2-hydroxy ethylacrylate, 2-hydroxyethylmethacrylate, 2-hydroxypropyl acrylate,2-hydroxypropylmethacrylate, 4-hydroxy butylacrylate, pentaerythritoltriacrylate; aliphatic monoesters or polyesters respectively having atleast one hydroxyl group, such as 2-hydroxy ethyl acetate, methyl3-hydroxy butylate, ethyl 3-hydroxy butylate, methyl 2-hydroxyisobutylate, ethyl 2-hydroxy isobutylate, methyl-3-hydroxy-2-methylpropionate, 2, dimethyl-3-hydroxy propionate, ethyl-6-hydroxy hexanoate,t-butyl-2-hydroxy isobutylate, diethyl-3-hydroxy gluate, ethyl lactate,isopropyl lactate, butyl isobutyl lactate, isobutyl lactate, ethylmandelate, dimethyl ethyl tartrate, ethyl tartrate, dibutyl tartrate,diethyl citrate, triethyl citrate, ethyl-2-hydroxy-caproate, diethylbis-(hydroxy methyl) malonate; aromatic esters respectively having atleast one hydroxyl group, such as 2-hydroxy ethyl benzoate, 2-hydroxyethyl salicylate, methyl-4-(hydroxy methyl) benzoate, methyl 4-hydroxybenzoate, ethyl 3-hydroxy benzoate, 4-methyl salicylate, ethylsalicylate, phenyl salicylate, propyl 4-hydroxy benzoate, phenyl3-hydroxy naphthanoate, monoethylene glycol monobenzoate, diethyleneglycol monobenzoate, triethylene glycol monobenzoate; alicyclic estersrestively having at least one hydroxyl group, such as hydroxybutyllactone, and others. The amount of the ester compound having at leastone hydroxyl group should be 0.001˜5 mol per mole of magnesium, orpreferably 0.01˜2 mol per mole of magnesium.

[0019] For the silicon compound having at least one alkoxy group, whichcan be used as another electron donor in the present invention, acompound which is represented by a general formula of R_(n)Si(OR)_(4-n)(here R is a hydrocarbon having 1˜12 carbons, while “n” is a naturalnumber from 0 to 3) is preferable. In particular, the followingcompounds can be used: dimethyldimethoxysilane, dimethyldiethoxysilane,diphenyldimethoxysilane, methylphenylmethoxysilane,diphenyldiethoxysilane, ethyltrimethoxysilane, vinyltrmethoxysilane,methyltrimethoxysilane, phenyltrmethoxysilane, methyltriethoxysilane,ethyltriethoxysilane, vinyltciethoxysilane, butyltriethoxysilane,phenyltriethoxysilane, ethyltdisopropoxysilane, vinyltributoxysilane,ethylsilicate, butylsilicate, methyltriarrloxysilane, etc. The amount ofsaid compound is preferably 0.05˜3 mol per mole of magnesium, or morepreferably 0.1˜2 mol.

[0020] As for the temperature for the contact-reaction of the magnesiumsolution, an ester compound having at least one hydroxyl group, and analkoxy silicon compound, the temperature of 0˜100° C. is appropriate, ormore preferably 10˜70° C.

[0021] For recrystalization of catalyst particles, the magnesiumcompound solution obtained as such is reacted with a mixture of a liquidtitanium compound represented by a general formula of Ti(OR)_(a)X_(4-a)(here R is a hydrocarbon group, X a halogen atom, “a” a natural numberfrom 0 to 4) and a compound represented by a general formula ofR_(n)SiCl_(4-n) (here R is hydrogen, an alkyl group, an alkoxy,haloalkyl, or aryl group having 1˜10 carbons, or halosilyl or ahalosilylalkyl group having 1˜8 carbons, and “n” a natural number from 0to 3). In the general formula, R is an allyl group having 1˜10 carbonatoms.

[0022] The types of titanium compounds which satisfy the general formulainclude 4-halogenated titanium such as TiCl₄, TiBr₄, and TiI₄;3-halogenated alkoxy-titanium such as Ti(OCH₃)Cl₃, Ti(OC₂H₅)Cl₃,Ti(OC₂H₅)Br₃, and Ti(O(i-C₄H₉))Br₃; 2-halogenated alkoxy-titaniumcompounds such as Ti(OCH₃)₂Cl₂, Ti(OC₂H₅)₂Cl₂, Ti(O(i-C₄H₉))₂Cl₂, andTi(OC₂H₅)₂Br₂; and tetra-alkoxy titanium such as Ti(OCH₃)₄, Ti(OC₂H₅)₄,and Ti(OC₄H₉)₄. A mixture of the above titanium compounds can also beused in the present invention. However, the preferable titaniumcompounds are those containing respectively halogen, or more preferablytitanium tetrachloride.

[0023] The types of silicon compounds satisfying the above generalformula of R_(n)SiCl_(4-n) (here R is hydrogen, an alkyl group, analkoxy, haloalkyl, or aryl group having 1˜10 carbons, or halosilyl or ahalosilylalkyl group having 1˜8 carbons, and “n” a natural number from 0to 3) include silicon tetrachloride; trichlorosilanes such asmethyltrichlorosilane, ethyltrichlorosilane, phenyltrichlorosilane;dichlorosilanes such as dimethyldichlorosilane, diethyldichlorosilane,di-phenyldichlorosilane, and methylphenyldichlorosilane;monochlorosilanes such as trimethylchlorosilane; and a mixture of thesesilicon compounds can also be used in the present invention, or mompreferably silicon tetrachloride can be used.

[0024] The amount of mixture of a titanium compound and a siliconcompound used during re-crystallization of magnesium compound solutionis appropriately 0.1˜200 mol per mole of magnesium compounds, preferably0.1˜100 mol, or more preferably 0.2˜80 mol. The molar ratio of thetitanium compound to the silicon compound in mixture is appropriately1:0.05˜0.95, or more preferably 1:0.1˜0.8.

[0025] When the magnesium compound solution is reacted with the mixtureof a titanium compound and a silicon compound, the shapes and the sizesof the resultant recrystallized solid constituents vary a great dealaccording to the reaction conditions. Hence, the reaction of themagnesium compound solution with the mixture of a titanium compound anda silicon compound should be carried out preferably at a sufficientlylow temperature to result in formation of solid constituents. Morepreferably, the reaction should be carried out by contact-reaction at−70˜70° C., or most preferably at −50˜50° C. After the contact-reaction,the reacting temperature is slowly raised for sufficient reaction forthe duration of 0.5˜5 hours at 50˜150° C.

[0026] The particles of said solid catalysts obtained during the aboveprocess can be further reacted with the titanium compounds. Thesetitanium compounds are titanium halides or halogenated alkoxy titaniumsrespectively with an alkoxy functional group of 1˜20 carbons. At tires,a mixture of these compounds can also be used. Of these compounds,however, a titanium halide or a halogenated alkoxy titanium compoundhaving an alkoxy functional group of 1˜8 carbons can be appropriatelyused, or more preferably a titanium tetrahalide can be used.

[0027] The catalyst produced according to the process of the presentinvention can be utilized for homo- or co-polymerization of ethylene. Inparticular, the catalyst is used in homo-polymerization of ethylene, andalso in copolymerization of ethylene and α-olefin such as propylene,1-butene, 1-pentene, 4-methyl-1-pentene, or 1-hexene having three ormore carbons.

[0028] The polymerization reaction in the presence of a catalyst in thepresent invention is carried out by means of using (i) a solid complextitanium catalyst of the present invention, comprising magnesium,titanium, halogen, and an electron donor, and (ii) a catalyst systemcomprising compounds of organic metals of Groups II or III of thePeriodic Table.

[0029] In the present invention, the solid complex titanium catalystconstituent can be used as a component in the polymerization reactionafter pre-polymerization with ethylene or α-olefin. Thepre-polymerization can be carried out in the presence of a hydrocarbonsolvent such as hexane, at a sufficiently low temperature, with ethyleneor α-olefin under pressure, in the presence of the above catalystconstituent and such organic aluminium compound as triethylaluminium.The pre-polymerization, by maintaining the shapes of catalysts bysurrounding the catalyst particles with polymers, is helpful inproducing good-quality post-polymerization shapes of polymers. Theweight ratio of polymers to catalysts after pre-polymerization isordinarily 0.1:1˜20:1.

[0030] The organometallic compound in the present invention can berepresented by a general formula of MR_(n), wherein, M stands for ametal constituent of Group II or IIIA in the Periodic Table, such asmagnesium, calcium, zinc, boron, aluminium, and gallium, R for an alkylgroup with 1˜20 carbons, such as a methyl, ethyl, butyl, hexyl, octyl,or decyl group, and n for the atomic valence of the metal constituent.As for more preferable organometallic compounds, a trialkyl aluminiumhaving an alkyl group of 1˜6 carbons, such as triethylaluminium andtriisobutylaluminium, or the mixture thereof can be utilized. Onoccasions, an organic aluminium compound having one or more halogen orhydride groups, such as ethylaluminium dichloride, diethylaluminiumchloride, ethylaluminium sesquichloride, or diisobutylaluminium hydridecan also be used.

[0031] As for the polymerization reaction, it is possible to carry outeither the gas phase or bulk polymerization in the absence of an organicsolvent, or the liquid slurry polymerization in the presence of anorganic solvent. These polymerization methods, however, are carried outin the absence of oxygen, water, or other compounds that may act ascatalytic poison.

[0032] The concentration of the solid complex titanium catalyst (i) withrespect to the polymerization reaction system, in case of liquid phaseslurry polymerization, is approximately 0.001˜5 mmol in terms oftitanium atoms in catalyst per one liter of the solvent, or morepreferably approximately 0.001˜0.5 mmol. As for the solvent, thefollowing compounds or the mixtures thereof can be used: alkanes such aspentane, hexane, heptane, n-octane, isooctane, cyclohexane,methylcyclohexane; alkylaromatics such as toluene, xylene, ethylbenzene,isopropylbenzene, ethyltoluene, n-propylbenzene, diethylbezene;halogenated aromatics such as chlorobenzene, chloronaphthalene,orthoichlorobenzene; and the mixtures thereof. In the case of gas phasepolymerization, the amount of the solid complex titanium catalyst (i)should be approximately 0.001˜5 mmol in terms of titanium atoms incatalyst per one liter of the polymerization reactant, preferablyapproximately 0.001˜1.0 mmol, or more preferably approximately 0.01˜0.5mmol. The preferable concentration of the organometallic compound (ii),as calculated by organometallic atom, is about 1˜2,000 mol per mole oftitanium atoms in catalyst (i), or more preferably about 5˜500 mol.

[0033] To secure a high reaction rate of polymerization, thepolymerization herein is carried out at a sufficiently high temperature,regardless of the polymerization process. Generally, the temperature ofapproximately 20˜200° C. is appropriate, or more preferablyapproximately 20˜95° C. The appropriate pressure of monomers at the timeof polymerization is the atmospheric to 100 atm, or more preferably 2˜50atm.

[0034] In the present invention, the changes in the molecular weightaccording to the amount of hydrogen consumption at the time ofpolymerization are shown as melt index (ASTM D 1238), which is generallyknown in the art The value of the melt index generally becomes greateras the molecular weight decreases.

[0035] The products obtained by the method of polymerization of thepresent invention are solid ethylene homopolymers or the copolymers ofethylene and α-olefin, which have excellent bulk density and fluidity.Since the yields of polymer are sufficiently high, there is no need forthe removal of catalyst residues.

[0036] The present invention is further described by means of theexamples and comparative examples as below but should not be confined orlimited to these examples.

EXAMPLE 1

[0037] A solid complex titanium catalyst was produced by means of thefollowing three steps:

[0038] (i) Step: Production of Magnesium Solution

[0039] Into a 1.0L reactor equipped with a mechanical stirrer, replacedwith nitrogen atmosphere, 9.5 g of MgCl₂ and 200 ml of decane wereplaced therein. After they were stirred at 300 rpm, 70 ml of 2-ethylhexanol was added thereto. The temperature was raised to 120° C., andthen the reaction was allowed to continue for three hours. Thehomogenous solution, which was obtained after the reaction, was cooledto room temperature, and then 100 ml of mineral oil (Kaydol produced byWitco, Inc. (US); white mineral oil, with viscosity of 63-70 centistokeat 40° C.) was added thereto, followed by stirring for one hour.

[0040] (ii) Step: Contact-Reaction of Magnesium Solution, EsterContaining a Hydroxyl Group and Alkoxy Silane Compound

[0041] To the magnesium solution, cooled to room temperature as above(25° C.), 14 ml of 2-hydroxyethyl methacrylate and 14.0 ml of silicontetraethoxide were added, and then the reaction was allowed to continuefor an hour.

[0042] (iii) Step: Treatment of Mixture of Titanium Compound and SiliconCompound

[0043] Into the above solution, a solution mixture of 50 ml of titaniumtetrachloride and 50 ml of silicon tetrachloride was dripped thereto forone hour at room temperature. After completing the dripping process, thetemperature of the reactor was raised to 70° C. during stirring, afterwhich was maintained at that temperature for one hour. Then, thetemperature of the reactor was lowered to room temperature, and afterstop stirring, the supernatant of the solution was removed, and theremaining solid layer was continuously instilled with 300 ml of decaneand 300 ml of titanium tetrachloride. There, the temperate was raised to100° C. and maintained thereat for two hours. After the reaction, thereactor was cooled to room tempera and was instilled with 400 ml ofhexane for washing until the removal of free unreacted titaniumtetrachloride. The titanium content of the solid catalyst so producedwas 5.6 wt %.

[0044] Polymerization

[0045] A 2-L high-pressure reactor was dried in an oven and assembledwhile hot. In order to make the inside of the reactor nitrogenatmosphere, nitrogen and vacuum were alternatively manipulated threeties in the reactor. It was then instilled with 1,000 ml of n-hexane,after which 1 mmol of triethylaluminium and the above solid catalyst by0.03 mmol in terms of titanium atoms were added thereto. Then, 2,000 mlof hydrogen was added. The temperature of the reactor was raised to 80°C. while suing at 700 rpm. The pressure of ethylene was adjusted to 100psi, and the polymerization was allowed to continue for an hour. Afterthe polymerization, the temperature of the reactor was lowered to roomtemperature, and an excessive amount of ethanol solution was added tothe polymerized matters. The polymer thus produced was collected byseparation and was dried in an oven at 50° C. for at least six hours,whereby polyethylene was obtained in the form of white powder.

[0046] The polymerization activity (cg of polyethylene divided by gramof catalyst) was calculated as the weight (kg) ratio of the polymers asproduced per the amount of catalysts so used (gram of catalyst). Theresults of polymerization are shown in Table 1, together with the bulkdensity (g/ml) of the polymers, and the melt index (g/10 minutes).

EXAMPLE 2

[0047] As in Step (i) of Example 1, 100 ml of decane was used whileproducing magnesium solution under the same conditions. Then, 200 ml ofmineral oil was added thereto for adjusting the viscosity therein toproduce catalysts as in Example 1. The titanium content of the catalystthus produced was 5.2 wt %. The polymerization was carded out as inExample 1, and the results thereof are shown in Table 1.

EXAMPLE 3

[0048] As in Step (i) of Example 1, 150 ml of decane was used whileproducing magnesium solution under the same conditions. Then, 150 ml ofmineral oil was added thereto for adjusting the viscosity therein toproduce catalysts as in Example 1. The titanium content of the catalystthus produced was 4.8 wt %. The polymerization was carded out as inExample 1, and the results thereof are shown in Table 1.

EXAMPLE 4

[0049] As in Step (i) of Example 1, 200 ml of decane with 100 ml ofmineral oil were used while producing magnesium solution under the sameconditions, and thus the catalysts were produced as in Example 1. Thetitanium content of the catalyst thus produced was 5.1 wt %. Thepolymerization was carried out as in Example 1, and the results thereofare shown in Table 1.

COMPARATIVE EXAMPLE 1

[0050] As in Step (i) of Example 1, 300 ml of decane was used whileproducing magnesium solution under the same conditions, and thus thecatalysts were produced as in Example 1 without adding mineral oil. Thetitanium content of the catalyst thus produced was 4.8 wt %. Thepolymerization was carried out as in Example 1, and the results thereofare shown in Table 1. TABLE 1 Results of Polymerization Activity (kg PE/Bulk Melting Distribution of Polymer Particles (wt %) g of Density Index840 500 250 177 105 74 <44 Example catalyst) (g/ml) (g/10 min) μm μm μumμm μm μm μm 1 4.1 0.40 3.52 0.0 0.2 3.4 21.2 63.8 10.8 0.6 2 4.2 0.393.73 0.0 0.4 4.8 27.2 51.0 15.4 1.2 3 4.0 0.41 3.67 0.0 0.0 7.2 24.849.2 17.2 0.8 4 4.0 0.39 3.83 0.0 0.3 6.9 22.9 54.3 14.9 0.7 CE* 1 3.80.36 3.21 1.2 8.6 12.4 17.8 44.8 12.8 2.4

[0051] As shown above, by way of the production process according to thepresent invention, it is possible to produce a new catalyst of highpolymerization activity for homo- and co-polymerization of ethylene,which can produce polymers of high bulk density with few fine particles.

What is claimed is:
 1. A method for producing a catalyst for homo- orco-polymerization of ethylene, which comprises the steps of: (i)preparing a magnesium solution by contact-reacting a halogenatedmagnesium compound with alcohol and then adding mineral oil thereto;(ii) reacting said solution with an ester compound having at least onehydroxyl group and a silicon compound having at least one alkoxy group;and (iii) reacting said solution with a mixture of a titanium compoundand a silicon compound.
 2. The method for producing a catalyst for homo-or co-polymerization of ethylene according to claim 1, wherein saidmineral oil is white oil, parafinic hydrocarbon oil, or silicone oil. 3.The method for producing a catalyst for homo- or co-polymerization ofethylene according to claim 1, wherein said ester compound having atleast one hydroxyl group is an unsaturated aliphatic acid ester havingat least one hydroxyl group, which is selected from the group consistingof 2-hydroxy ethylacrylate, 2-hydroxy ethylmethacrylate, 2-hydroxypropyl acrylate, 2-hydroxy propylmethacrylate, 4-hydroxy butylacrylate,and pentaerythritol tri-acrylate; an aliphatic monoester or polyesterhaving at least one hydroxyl group, which is selected from the groupconsisting of 2-hydroxy ethyl acetate, methyl 3-hydroxy butylate, ethyl3-hydroxy butylate, methyl 2-hydroxy isobutylate, ethyl 2-hydroxyisobutylate, methyl-3-hydroxy-2-methyl propionate,2,2-dimethyl-3-hydroxy propionate, ethyl-6-hydroxy hexanoate,t-butyl-2-hydroxy isobutylate, diethyl-3-hydroxy glutarate, ethyllactate, isopropyl lactate, butyl isobutyl lactate, isobutyl lactate,ethyl mandelate, dimethyl ethyl tartrate, ethyl tartrate, dibutyltartrate, diethyl citrate, triethyl citrate, ethyl-2-hydroxy-caproate,and diethyl bis-(hydroxymethyl) malonate; an aromatic ester having atleast one hydroxyl group, which is selected from the group consisting of2-hydroxy ethyl benzoate, 2-hydroxy ethyl salicylate, methyl-4-(hydroxymethyl) benzoate, methyl-4-hydroxy benzoate, ethyl-3-hydroxy benzoate,4-methyl salicylate, ethyl salicylate, phenyl salicylate,propyl-4-hydroxy benzoate, phenyl 3-hydroxy naphthanoate, monoethyleneglycol monobenzoate, diethylene glycol monobenzoate, and triethyleneglycol monobenzoate; and an alicyclic ester having at least one hydroxylgroup such as hydroxy butyl lactone; and wherein said silicon compoundhaving at least one alkoxy group is selected from the group consistingof dimethyldimethoxysilane, dimethyldiethoxysilane,diphenyldimethoxysilane, methylphenylmethoxysilane,diphenyldiethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane,methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane,ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane,phenyltriethoxysilane, ethyltriisopropoxysilane, vinyltributoxysilane,ethylsilicate, butylsilicate, and methyltriaryloxysilane.
 4. The methodfor producing a catalyst for homo- or co-polymerization of ethyleneaccording to claim 1, wherein said titanium compound is represented by ageneral formula of Ti(OR)_(a)X_(4-a), where R stands for a hydrocarbongroup, X for a halogen atom, and a for a natural number of 0˜4; andwherein said silicon compound is represented by a general formula ofR_(n)SiCl_(4−n), where R stands for hydrogen; an alkyl, alkoxy,haloalkyl, or aryl group having 1˜10 carbons; or a halosilyl orhalosilylalkyl group having 1˜8 carbons; and n for a natural number of0˜3.
 5. The method for producing a catalyst for homo- orco-polymerization of ethylene according to claim 4, wherein saidtitanium compound is a 4-halogenated titanium, which is selected fromthe group consisting of TiCl₄, TiBr₄, and TiI₄; a 3-halogenatedalkoxytitanium, which is selected from the group consisting ofTi(OCH₃)Cl₃, Ti(OC₂H₅)Cl₃, Ti(OC₂H₅)Br₃, and Ti(O(i-C₄H₉)Br₃; a2-halogenated alkoxytitanium, which is selected from the groupconsisting of Ti(OCH₃)₂Cl₂, Ti(OC₂H₅)₂Cl₂, Ti(O(i-C₄H₉))₂Cl₂, andTi(OC₂H₅)₂Br₂; and a tetralkoxytitanium, which is selected from thegroup consisting of Ti(OCH₃)₄, Ti(OC₂H₅)₄, and Ti(OC₄H₉)₄; or mixturesthereof; and wherein said silicon compound is a trichlorosilane, whichis selected from the group consisting of silicon tetrachloride,methyltrichlorosilane, ethyltrichlorosilane, and phenyl-trichlorosilane;a dichlorosilane, which is selected from the group consisting ofdimethylchlorosilane, diethyldichlorosilane, diphenyldichlorosilane, andmethylphenyldichlorosilane; a monochlorosilane such astrimethylchlorosilane; or mixtures thereof.
 6. The method for producinga catalyst for homo- or co-polymerization of ethylene according to claim1, wherein said titanium compound is titanium tetrachloride, and saidsilicon compound is silicon tetrachloride.